gases and ions tests Flashcards
catalytic decomposition of hydrogen peroxide becomes …
oxygen and water
test for oxygen
glowing splint –> relights
test for carbon dioxide
limewater turns milky
test for chlorine
hold damp litmus paper over – bleaches
test for ammonia
hold damp litmus paper over – changes from red to blue
meaning of cation
positive ion
what test is used for sodium potassium lithium barium calcium and copper and what colour is observed?
flame test - sodium : yellow orange, potassium : lilac, lithium : crimson red, barium : green, calcium : brick red, copper : bluish green
what test is used for calcium, copper, iron(ll), iron(lll), magnesium and aluminium and what is observed?
add dilute sodium hydroxide – calcium : while ppt, copper : pale blue ppt, iron(ll) : grey green ppt, iron(lll) : red-brown ppt, magnesium : white ppt, aluminium: white ppt that re-dissolves
what test is used for hydrogen and ammonium? + observations
litmus paper – ammonium : add NaOH, warm and test gas with red litmus, hydrogen : dip damp blue litmus paper in ( blue –> red)
what do you call negative ions?
anions
what acid do you use to acidify chloride bromide and iodide before testing
nitric acid
test for chloride bromide and iodide + observations
add dilute silver nitrate – chloride : white ppt, bromide : pale cream ppt, iodide : yellow ppt
test for sulphate + observation
acidify with Hal and add dilute barium chloride – white ppt
test for carbonate + observation
add any dilute acid – bubbles of CO2
test for hydroxide + observation
dip red litmus paper – turns blue
